Auto merge of #114089 - Urgau:allow-with-implied-by, r=petrochenkov

Add an allow attribute suggestion along with the implied by suggestion

This PR adds an `#[allow(...)]` attribute hep suggestion along with the implied by suggestion:
```diff
  note: `-W dead-code` implied by `-W unused`
+ help: to override `-W unused` add `#[allow(dead_code)]`
```

This PR also adds the `OnceHelp` lint level (similar to `OnceNote`) to only put the help message one time, like the implied note.

Related to #114030

compiler/rustc_errors/src/annotate_snippet_emitter_writer.rs

@@ -91,7 +91,7 @@ fn annotation_type_for_level(level: Level) -> AnnotationType {
         }
         Level::Warning(_) => AnnotationType::Warning,
         Level::Note | Level::OnceNote => AnnotationType::Note,
-        Level::Help => AnnotationType::Help,
+        Level::Help | Level::OnceHelp => AnnotationType::Help,
         // FIXME(#59346): Not sure how to map this level
         Level::FailureNote => AnnotationType::Error,
         Level::Allow => panic!("Should not call with Allow"),

compiler/rustc_errors/src/diagnostic.rs

@@ -270,6 +270,7 @@ impl Diagnostic {
             | Level::Note
             | Level::OnceNote
             | Level::Help
+            | Level::OnceHelp
             | Level::Allow
             | Level::Expect(_) => false,
         }
@@ -532,6 +533,13 @@ impl Diagnostic {
         self
     }
 
+    /// Prints the span with a help above it.
+    /// This is like [`Diagnostic::help()`], but it gets its own span.
+    pub fn help_once(&mut self, msg: impl Into<SubdiagnosticMessage>) -> &mut Self {
+        self.sub(Level::OnceHelp, msg, MultiSpan::new(), None);
+        self
+    }
+
     /// Add a help message attached to this diagnostic with a customizable highlighted message.
     pub fn highlighted_help(&mut self, msg: Vec<(String, Style)>) -> &mut Self {
         self.sub_with_highlights(Level::Help, msg, MultiSpan::new(), None);

compiler/rustc_errors/src/lib.rs

@@ -1390,7 +1390,7 @@ impl HandlerInner {
                 debug!(?self.emitted_diagnostics);
                 let already_emitted_sub = |sub: &mut SubDiagnostic| {
                     debug!(?sub);
-                    if sub.level != Level::OnceNote {
+                    if sub.level != Level::OnceNote && sub.level != Level::OnceHelp {
                         return false;
                     }
                     let mut hasher = StableHasher::new();
@@ -1792,6 +1792,8 @@ pub enum Level {
     /// A note that is only emitted once.
     OnceNote,
     Help,
+    /// A help that is only emitted once.
+    OnceHelp,
     FailureNote,
     Allow,
     Expect(LintExpectationId),
@@ -1816,7 +1818,7 @@ impl Level {
             Note | OnceNote => {
                 spec.set_fg(Some(Color::Green)).set_intense(true);
             }
-            Help => {
+            Help | OnceHelp => {
                 spec.set_fg(Some(Color::Cyan)).set_intense(true);
             }
             FailureNote => {}
@@ -1831,7 +1833,7 @@ impl Level {
             Fatal | Error { .. } => "error",
             Warning(_) => "warning",
             Note | OnceNote => "note",
-            Help => "help",
+            Help | OnceHelp => "help",
             FailureNote => "failure-note",
             Allow => panic!("Shouldn't call on allowed error"),
             Expect(_) => panic!("Shouldn't call on expected error"),

compiler/rustc_middle/src/lint.rs

@@ -225,6 +225,9 @@ pub fn explain_lint_level_source(
                 err.note_once(format!(
                     "`{flag} {hyphen_case_lint_name}` implied by `{flag} {hyphen_case_flag_val}`"
                 ));
+                err.help_once(format!(
+                    "to override `{flag} {hyphen_case_flag_val}` add `#[allow({name})]`"
+                ));
             }
         }
         LintLevelSource::Node { name: lint_attr_name, span, reason, .. } => {

src/tools/clippy/tests/ui-toml/absolute_paths/absolute_paths.allow_crates.stderr

@@ -5,6 +5,7 @@ LL |     std::f32::MAX;
    |     ^^^^^^^^^^^^^
    |
    = note: `-D clippy::absolute-paths` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::absolute_paths)]`
 
 error: consider bringing this path into scope with the `use` keyword
   --> $DIR/absolute_paths.rs:41:5

src/tools/clippy/tests/ui-toml/absolute_paths/absolute_paths.disallow_crates.stderr

@@ -5,6 +5,7 @@ LL |     std::f32::MAX;
    |     ^^^^^^^^^^^^^
    |
    = note: `-D clippy::absolute-paths` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::absolute_paths)]`
 
 error: consider bringing this path into scope with the `use` keyword
   --> $DIR/absolute_paths.rs:41:5

src/tools/clippy/tests/ui-toml/allow_mixed_uninlined_format_args/uninlined_format_args.stderr

@@ -5,6 +5,7 @@ LL |     println!("val='{}'", local_i32);
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::uninlined-format-args` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::uninlined_format_args)]`
 help: change this to
    |
 LL -     println!("val='{}'", local_i32);
@@ -30,6 +31,7 @@ LL |     println!("Hello {} is {:.*}", "x", local_i32, local_f64);
    |                                   ^^^
    |
    = note: `-D clippy::print-literal` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::print_literal)]`
 help: try
    |
 LL -     println!("Hello {} is {:.*}", "x", local_i32, local_f64);

src/tools/clippy/tests/ui-toml/arithmetic_side_effects_allowed/arithmetic_side_effects_allowed.stderr

@@ -5,6 +5,7 @@ LL |     let _ = Baz + Baz;
    |             ^^^^^^^^^
    |
    = note: `-D clippy::arithmetic-side-effects` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::arithmetic_side_effects)]`
 
 error: arithmetic operation that can potentially result in unexpected side-effects
   --> $DIR/arithmetic_side_effects_allowed.rs:80:13

src/tools/clippy/tests/ui-toml/array_size_threshold/array_size_threshold.stderr

@@ -7,6 +7,7 @@ LL | const ABOVE: [u8; 11] = [0; 11];
    | help: make this a static item: `static`
    |
    = note: `-D clippy::large-const-arrays` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::large_const_arrays)]`
 
 error: allocating a local array larger than 10 bytes
   --> $DIR/array_size_threshold.rs:4:25
@@ -16,6 +17,7 @@ LL | const ABOVE: [u8; 11] = [0; 11];
    |
    = help: consider allocating on the heap with `vec![0; 11].into_boxed_slice()`
    = note: `-D clippy::large-stack-arrays` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::large_stack_arrays)]`
 
 error: allocating a local array larger than 10 bytes
   --> $DIR/array_size_threshold.rs:8:17

src/tools/clippy/tests/ui-toml/await_holding_invalid_type/await_holding_invalid_type.stderr

@@ -6,6 +6,7 @@ LL |     let _x = String::from("hello");
    |
    = note: strings are bad (from clippy.toml)
    = note: `-D clippy::await-holding-invalid-type` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::await_holding_invalid_type)]`
 
 error: `std::net::Ipv4Addr` may not be held across an `await` point per `clippy.toml`
   --> $DIR/await_holding_invalid_type.rs:10:9

src/tools/clippy/tests/ui-toml/conf_deprecated_key/conf_deprecated_key.stderr

@@ -18,6 +18,7 @@ LL | fn cognitive_complexity() {
    |
    = help: you could split it up into multiple smaller functions
    = note: `-D clippy::cognitive-complexity` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::cognitive_complexity)]`
 
 error: aborting due to previous error; 2 warnings emitted
 

src/tools/clippy/tests/ui-toml/dbg_macro/dbg_macro.stderr

@@ -5,6 +5,7 @@ LL |     if let Some(n) = dbg!(n.checked_sub(4)) { n } else { n }
    |                      ^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::dbg-macro` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::dbg_macro)]`
 help: remove the invocation before committing it to a version control system
    |
 LL |     if let Some(n) = n.checked_sub(4) { n } else { n }

src/tools/clippy/tests/ui-toml/disallowed_macros/disallowed_macros.stderr

@@ -5,6 +5,7 @@ LL |     println!("one");
    |     ^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::disallowed-macros` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::disallowed_macros)]`
 
 error: use of a disallowed macro `std::println`
   --> $DIR/disallowed_macros.rs:11:5

src/tools/clippy/tests/ui-toml/disallowed_names_append/disallowed_names.stderr

@@ -5,6 +5,7 @@ LL |     let foo = "bar";
    |         ^^^
    |
    = note: `-D clippy::disallowed-names` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::disallowed_names)]`
 
 error: use of a disallowed/placeholder name `ducks`
   --> $DIR/disallowed_names.rs:7:9

src/tools/clippy/tests/ui-toml/disallowed_names_replace/disallowed_names.stderr

@@ -5,6 +5,7 @@ LL |     let ducks = ["quack", "quack"];
    |         ^^^^^
    |
    = note: `-D clippy::disallowed-names` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::disallowed_names)]`
 
 error: aborting due to previous error
 

src/tools/clippy/tests/ui-toml/doc_valid_idents_append/doc_markdown.stderr

@@ -5,6 +5,7 @@ LL | /// TestItemThingyOfCoolness might sound cool but is not on the list and sh
    |     ^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::doc-markdown` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::doc_markdown)]`
 help: try
    |
 LL | /// `TestItemThingyOfCoolness` might sound cool but is not on the list and should be linted.

src/tools/clippy/tests/ui-toml/doc_valid_idents_replace/doc_markdown.stderr

@@ -5,6 +5,7 @@ LL | /// OAuth and LaTeX are inside Clippy's default list.
    |     ^^^^^
    |
    = note: `-D clippy::doc-markdown` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::doc_markdown)]`
 help: try
    |
 LL | /// `OAuth` and LaTeX are inside Clippy's default list.

src/tools/clippy/tests/ui-toml/excessive_nesting/excessive_nesting.stderr

@@ -6,6 +6,7 @@ LL |                 let w = { 3 };
    |
    = help: try refactoring your code to minimize nesting
    = note: `-D clippy::excessive-nesting` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::excessive_nesting)]`
 
 error: this block is too nested
   --> $DIR/excessive_nesting.rs:67:17

src/tools/clippy/tests/ui-toml/expect_used/expect_used.stderr

@@ -6,6 +6,7 @@ LL |     let _ = opt.expect("");
    |
    = note: if this value is `None`, it will panic
    = note: `-D clippy::expect-used` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::expect_used)]`
 
 error: used `expect()` on a `Result` value
   --> $DIR/expect_used.rs:12:13

src/tools/clippy/tests/ui-toml/fn_params_excessive_bools/test.stderr

@@ -6,6 +6,7 @@ LL | fn g(_: bool, _: bool) {}
    |
    = help: consider refactoring bools into two-variant enums
    = note: `-D clippy::fn-params-excessive-bools` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::fn_params_excessive_bools)]`
 
 error: aborting due to previous error
 

src/tools/clippy/tests/ui-toml/functions_maxlines/test.stderr

@@ -8,6 +8,7 @@ LL | | }
    | |_^
    |
    = note: `-D clippy::too-many-lines` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::too_many_lines)]`
 
 error: this function has too many lines (4/1)
   --> $DIR/test.rs:25:1

src/tools/clippy/tests/ui-toml/ifs_same_cond/ifs_same_cond.stderr

@@ -10,6 +10,7 @@ note: same as this
 LL |     if x.get() {
    |        ^^^^^^^
    = note: `-D clippy::ifs-same-cond` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::ifs_same_cond)]`
 
 error: aborting due to previous error
 

src/tools/clippy/tests/ui-toml/large_futures/large_futures.stderr

@@ -5,6 +5,7 @@ LL |     should_warn().await;
    |     ^^^^^^^^^^^^^ help: consider `Box::pin` on it: `Box::pin(should_warn())`
    |
    = note: `-D clippy::large-futures` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::large_futures)]`
 
 error: aborting due to previous error
 

src/tools/clippy/tests/ui-toml/large_include_file/large_include_file.stderr

@@ -6,6 +6,7 @@ LL | const TOO_BIG_INCLUDE_BYTES: &[u8; 654] = include_bytes!("too_big.txt");
    |
    = note: the configuration allows a maximum size of 600 bytes
    = note: `-D clippy::large-include-file` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::large_include_file)]`
    = note: this error originates in the macro `include_bytes` (in Nightly builds, run with -Z macro-backtrace for more info)
 
 error: attempted to include a large file

src/tools/clippy/tests/ui-toml/lint_decimal_readability/test.stderr

@@ -5,6 +5,7 @@ LL |     let _fail1 = 100_200_300.123456789;
    |                  ^^^^^^^^^^^^^^^^^^^^^ help: consider: `100_200_300.123_456_789`
    |
    = note: `-D clippy::inconsistent-digit-grouping` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::inconsistent_digit_grouping)]`
 
 error: long literal lacking separators
   --> $DIR/test.rs:22:18
@@ -13,6 +14,7 @@ LL |     let _fail2 = 100200300.300200100;
    |                  ^^^^^^^^^^^^^^^^^^^ help: consider: `100_200_300.300_200_100`
    |
    = note: `-D clippy::unreadable-literal` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::unreadable_literal)]`
 
 error: aborting due to 2 previous errors
 

src/tools/clippy/tests/ui-toml/min_ident_chars/min_ident_chars.stderr

@@ -5,6 +5,7 @@ LL | use extern_types::Aaa;
    |                   ^^^
    |
    = note: `-D clippy::min-ident-chars` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::min_ident_chars)]`
 
 error: this ident is too short (3 <= 3)
   --> $DIR/min_ident_chars.rs:10:5

src/tools/clippy/tests/ui-toml/min_rust_version/min_rust_version.stderr

@@ -5,6 +5,7 @@ LL |     let _: Option<u64> = Some(&16).map(|b| *b);
    |                          ^^^^^^^^^^^^^^^^^^^^^ help: consider calling the dedicated `cloned` method: `Some(&16).cloned()`
    |
    = note: `-D clippy::map-clone` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::map_clone)]`
 
 error: aborting due to previous error
 

src/tools/clippy/tests/ui-toml/missing_enforced_import_rename/conf_missing_enforced_import_rename.stderr

@@ -5,6 +5,7 @@ LL | use std::process::{exit as wrong_exit, Child as Kid};
    |                    ^^^^^^^^^^^^^^^^^^ help: try: `exit as goodbye`
    |
    = note: `-D clippy::missing-enforced-import-renames` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::missing_enforced_import_renames)]`
 
 error: this import should be renamed
   --> $DIR/conf_missing_enforced_import_rename.rs:6:1

src/tools/clippy/tests/ui-toml/module_inception/module_inception.stderr

@@ -7,6 +7,7 @@ LL | |         }
    | |_________^
    |
    = note: `-D clippy::module-inception` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::module_inception)]`
 
 error: module has the same name as its containing module
   --> $DIR/module_inception.rs:11:5

src/tools/clippy/tests/ui-toml/nonstandard_macro_braces/conf_nonstandard_macro_braces.stderr

@@ -5,6 +5,7 @@ LL |     let _ = vec! {1, 2, 3};
    |             ^^^^^^^^^^^^^^ help: consider writing: `vec![1, 2, 3]`
    |
    = note: `-D clippy::nonstandard-macro-braces` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::nonstandard_macro_braces)]`
 
 error: use of irregular braces for `format!` macro
   --> $DIR/conf_nonstandard_macro_braces.rs:44:13

src/tools/clippy/tests/ui-toml/print_macro/print_macro.stderr

@@ -5,6 +5,7 @@ LL |     print!("{n}");
    |     ^^^^^^^^^^^^^
    |
    = note: `-D clippy::print-stdout` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::print_stdout)]`
 
 error: use of `eprint!`
   --> $DIR/print_macro.rs:7:5
@@ -13,6 +14,7 @@ LL |     eprint!("{n}");
    |     ^^^^^^^^^^^^^^
    |
    = note: `-D clippy::print-stderr` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::print_stderr)]`
 
 error: aborting due to 2 previous errors
 

src/tools/clippy/tests/ui-toml/pub_crate_missing_docs/pub_crate_missing_doc.stderr

@@ -5,6 +5,7 @@ LL |     pub(crate) fn crate_no_docs() {}
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::missing-docs-in-private-items` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::missing_docs_in_private_items)]`
 
 error: missing documentation for a function
   --> $DIR/pub_crate_missing_doc.rs:15:5

src/tools/clippy/tests/ui-toml/semicolon_block/both.stderr

@@ -5,6 +5,7 @@ LL |     { unit_fn_block(); }
    |     ^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::semicolon-outside-block` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::semicolon_outside_block)]`
 help: put the `;` here
    |
 LL -     { unit_fn_block(); }
@@ -33,6 +34,7 @@ LL | |     };
    | |______^
    |
    = note: `-D clippy::semicolon-inside-block` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::semicolon_inside_block)]`
 help: put the `;` here
    |
 LL ~         unit_fn_block();

src/tools/clippy/tests/ui-toml/semicolon_block/semicolon_inside_block.stderr

@@ -8,6 +8,7 @@ LL | |     };
    | |______^
    |
    = note: `-D clippy::semicolon-inside-block` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::semicolon_inside_block)]`
 help: put the `;` here
    |
 LL ~         unit_fn_block();

src/tools/clippy/tests/ui-toml/semicolon_block/semicolon_outside_block.stderr

@@ -5,6 +5,7 @@ LL |     { unit_fn_block(); }
    |     ^^^^^^^^^^^^^^^^^^^^
    |
    = note: `-D clippy::semicolon-outside-block` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::semicolon_outside_block)]`
 help: put the `;` here
    |
 LL -     { unit_fn_block(); }

src/tools/clippy/tests/ui-toml/strict_non_send_fields_in_send_ty/test.stderr

@@ -11,6 +11,7 @@ LL |     rc_is_not_send: Rc<String>,
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^
    = help: use a thread-safe type that implements `Send`
    = note: `-D clippy::non-send-fields-in-send-ty` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::non_send_fields_in_send_ty)]`
 
 error: some fields in `MultiField<T>` are not safe to be sent to another thread
   --> $DIR/test.rs:19:1

src/tools/clippy/tests/ui-toml/struct_excessive_bools/test.stderr

@@ -8,6 +8,7 @@ LL | | }
    |
    = help: consider using a state machine or refactoring bools into two-variant enums
    = note: `-D clippy::struct-excessive-bools` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::struct_excessive_bools)]`
 
 error: aborting due to previous error
 

src/tools/clippy/tests/ui-toml/suppress_lint_in_const/test.stderr

@@ -18,6 +18,7 @@ LL |     x[index];
    |
    = help: consider using `.get(n)` or `.get_mut(n)` instead
    = note: `-D clippy::indexing-slicing` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::indexing_slicing)]`
 
 error: indexing may panic
   --> $DIR/test.rs:46:5

src/tools/clippy/tests/ui-toml/toml_disallow/conf_french_disallowed_name.stderr

@@ -5,6 +5,7 @@ LL | fn test(toto: ()) {}
    |         ^^^^
    |
    = note: `-D clippy::disallowed-names` implied by `-D warnings`
+   = help: to override `-D warnings` add `#[allow(clippy::disallowed_names)]`
 
 error: use of a disallowed/placeholder name `toto`
   --> $DIR/conf_french_disallowed_name.rs:9:9